What Are the Best Probiotics for Fatty Liver?

Fatty liver disease is increasingly common, often linked to poor diet, obesity, and metabolic disorders. While lifestyle changes remain key in managing the condition, research suggests probiotics may support liver health by influencing gut bacteria and reducing inflammation.

Understanding which probiotic strains are most beneficial can help guide dietary choices or supplementation for those looking to improve liver function.

Gut-Liver Interplay In Lipid Balance

The gut and liver maintain a dynamic relationship that significantly influences lipid metabolism. The liver processes dietary fats, synthesizes lipoproteins, and regulates cholesterol levels, while gut microbiota modulates these processes through microbial metabolites, bile acid transformation, and intestinal permeability. Disruptions in this balance, often caused by dysbiosis—an imbalance in gut microbial composition—can contribute to excessive fat accumulation in liver cells, a hallmark of non-alcoholic fatty liver disease (NAFLD).

Short-chain fatty acids (SCFAs), produced by gut bacteria through fiber fermentation, play a key role in lipid regulation. Butyrate, acetate, and propionate influence hepatic lipid metabolism by modulating gene expression related to fatty acid oxidation and lipogenesis. Propionate suppresses fat synthesis by inhibiting sterol regulatory element-binding protein-1c (SREBP-1c), while butyrate enhances mitochondrial function and β-oxidation, reducing liver fat. A study in Hepatology (2021) found that individuals with NAFLD had lower levels of SCFA-producing bacteria, suggesting probiotics may help restore microbial balance and improve lipid homeostasis.

Bile acid metabolism also links gut microbiota to liver function. Primary bile acids, synthesized in the liver from cholesterol, are transformed by gut bacteria into secondary bile acids, which regulate lipid and glucose metabolism. Lactobacillus and Bifidobacterium strains enhance bile acid deconjugation and receptor activation, particularly through the farnesoid X receptor (FXR) and Takeda G-protein-coupled receptor 5 (TGR5). FXR activation suppresses hepatic lipogenesis and promotes fatty acid oxidation, while TGR5 signaling enhances energy expenditure. Dysbiosis can impair these pathways, leading to bile acid dysregulation and exacerbating fat accumulation in the liver.

Intestinal permeability also affects liver lipid balance. A compromised gut barrier allows endotoxins like lipopolysaccharides (LPS) to enter the portal circulation, triggering hepatic inflammation and insulin resistance, both of which contribute to fat buildup. Studies show probiotic supplementation strengthens tight junction integrity in the gut, reducing endotoxin translocation and liver inflammation. A randomized controlled trial in The American Journal of Clinical Nutrition (2022) found that probiotic intervention in NAFLD patients significantly reduced serum LPS levels, improving liver enzyme profiles and decreasing hepatic fat content.

Commonly Explored Strains

Several probiotic strains have been investigated for their role in supporting liver health, particularly in individuals with fatty liver disease. These strains influence lipid metabolism, bile acid regulation, and gut barrier integrity. Among the most studied are Lactobacillus, Bifidobacterium, and Saccharomyces species, each offering distinct mechanisms that may contribute to improved liver function.

Lactobacillus

Species within the Lactobacillus genus have been widely studied for their effects on lipid metabolism and gut-liver interactions. Certain strains, such as Lactobacillus rhamnosus GG and Lactobacillus plantarum, modulate bile acid metabolism, which plays a role in lipid digestion and cholesterol homeostasis. A randomized controlled trial in Nutrients (2021) found that Lactobacillus plantarum supplementation reduced hepatic fat accumulation and improved liver enzyme levels in NAFLD patients. The proposed mechanism involves enhanced bile salt hydrolase activity, which promotes FXR activation and reduces hepatic lipogenesis.

Additionally, Lactobacillus strains influence SCFA production, particularly butyrate, which supports mitochondrial function and fatty acid oxidation in hepatocytes. A study in Gut Microbes (2022) reported that Lactobacillus rhamnosus supplementation increased butyrate-producing bacteria in the gut, correlating with reduced liver fat content.

Bifidobacterium

The Bifidobacterium genus has also been explored for its potential benefits in fatty liver disease. Strains such as Bifidobacterium longum and Bifidobacterium breve regulate lipid metabolism and improve gut barrier function. A clinical trial in The Journal of Hepatology (2022) found that Bifidobacterium longum supplementation reduced hepatic steatosis and improved insulin sensitivity in NAFLD patients, likely due to increased SCFA production, particularly propionate, which inhibits lipogenesis by downregulating SREBP-1c expression.

Beyond SCFA production, Bifidobacterium species strengthen tight junction proteins in the gut, reducing LPS translocation and lowering liver inflammation. Research in Clinical Nutrition (2021) demonstrated that Bifidobacterium breve supplementation improved gut barrier integrity, reducing markers of liver inflammation.

Saccharomyces

Unlike Lactobacillus and Bifidobacterium, which are bacterial probiotics, Saccharomyces is a genus of beneficial yeast studied for its effects on liver health. Saccharomyces boulardii has been shown to modulate gut microbiota composition and reduce oxidative stress in the liver. A study in Frontiers in Microbiology (2022) found that Saccharomyces boulardii supplementation improved liver enzyme profiles and reduced hepatic fat accumulation in NAFLD patients by outcompeting pathogenic bacteria and lowering systemic inflammation.

Additionally, Saccharomyces boulardii influences bile acid metabolism by promoting the growth of bacteria that enhance bile acid deconjugation, facilitating FXR activation and reducing hepatic lipid accumulation. A randomized controlled trial in The American Journal of Gastroenterology (2021) reported that Saccharomyces boulardii supplementation led to a significant decrease in serum triglyceride levels and improved liver function markers.

Factors Affecting Microbial Diversity

Gut microbiota composition is shaped by diet, environmental factors, and physiological conditions, all of which influence metabolic processes relevant to liver health. A diet rich in whole grains, legumes, and fibrous vegetables fosters the growth of SCFA-producing bacteria, which support hepatic lipid metabolism. In contrast, excessive intake of processed foods, refined sugars, and saturated fats reduces microbial diversity and promotes pro-inflammatory bacterial strains.

Micronutrients such as choline and vitamin D also contribute to microbial balance. Choline, found in eggs, fish, and lean meats, supports lipid transport and prevents hepatic fat accumulation. Deficiency in choline has been linked to gut microbiota changes that promote dysbiosis and hepatic steatosis. Vitamin D levels also influence microbial composition, with sufficient levels supporting the growth of beneficial Lactobacillus and Bifidobacterium species.

Medications further impact microbial populations. Antibiotics can disrupt microbial equilibrium by eliminating beneficial bacteria, while proton pump inhibitors (PPIs) alter gut microbiota by reducing gastric acidity, allowing bacterial overgrowth that may negatively affect bile acid metabolism. Individuals at risk for fatty liver disease may benefit from strategies that restore microbial balance after medication use, such as incorporating probiotic-rich foods or prebiotic fibers.

Fermented Foods With Probiotic Cultures

Fermented foods provide a natural way to introduce beneficial probiotic strains that may support liver function. Traditional fermentation methods encourage the growth of lactic acid bacteria and yeast, resulting in foods that contain live microbial cultures capable of influencing gut microbiota composition.

Yogurt and kefir are among the most accessible sources of probiotics, with kefir offering a broader spectrum of bacterial and yeast species. While yogurt primarily contains Lactobacillus and Bifidobacterium strains, kefir includes additional microbes such as Saccharomyces and Leuconostoc, which may enhance bile acid metabolism. Studies on kefir consumption have shown improvements in lipid profiles, with reductions in LDL cholesterol and triglycerides, suggesting potential benefits for individuals managing fatty liver disease.

Fermented vegetables like kimchi and sauerkraut provide Lactobacillus plantarum and Lactobacillus brevis, bacteria that break down fibrous plant compounds and produce metabolites influencing lipid metabolism. The fermentation process also enhances polyphenol bioavailability, compounds linked to reduced hepatic fat accumulation. Regular consumption of these foods has been associated with beneficial shifts in gut microbiota composition, supporting metabolic health.